Should i tell my freind i used his laptop without washing my hands?

he bites his nails alot too. its been about 2 weeks now. he is still fine, but im not. I have bad anxiety over this. I researched what can happen to him, theres alot of diseases or parasites that i could have given him. I dont have a deadly disease but mayby i gave him parasites or something. I dont know if I have any but i read that everybody has some of them. My fear is that his health will suffer from this or he may die, or p on the disease to others. I read one website that says ingesting fecal matter may cause cancer. Do I have the responsibility to tell him just so he knows and has a heads up? it would be so embaring, but mayby it is the right thing to do.